Device for attaching conductors to brushes



W. SIEBENMORGEN. DEVICE FOR ATTACHING CONDUCTORS T0 BRUSHES. APPLICATION HLED APR. 3, 1922.

1,433,687. Patented oct. 31, 1922.

I /NVE/I/TR Arron/ver Patented Oct. 31, 1922.

lUNITED STATES PATENT OFFICE.

WILLIAMSIEBENMORGEN, OF WESTFIELD, NEW JERSEY, ASSIGNOR TO COBLISS CARBON COMPANY, INCORPORATED, OF BRADFORD, PENNSYLVANIA, A COR- PORATION OF PENNSYLVANIA.

DEVICE FOR ATTACHING CONDUCTORS T0 BRUSHES.

Application led April 3, 1922;

To all 'whom t may concern Be it known that I, WILLIAM SIEBENMOR- GEN, a citizen of the United States, residing in Westfield, county of Union, and State of New Jersey, have invented certain new and useful Improvements in Devices for Attaching Conductors to Brushes, of which the following is a specification.

This invention relates to devices for attaching conductors to brushes for dynamoelectric apparatus.

The present application is, in part, a continuation of the subject matter disclosed in my co-pendin application Serial No. 335,597. filed ovember4, 1919, for devices for attaching conductors to carbon brushes, certain of ,the claimsherein, in substance, being divided out of the said co-pending case.

Ay good understanding of the invention may now be had from the following description thereof, reference being made to the accompanying drawings in which:

Figure 1 is a view showing a front elevation of one form of embodiment of the invention;

Figures 2 and 3 are views showing sections of Figure 1 on lines II-II and III-III, respectively, looking in the directions of the arrows;

Figures 4-and 5 are views similar to Figures` 2 and 3, respectively, showing a modified form of embodiment of the invention;

Figure 6 is a yview showing the pigtail flattened in accordance with this invention; and

Figure 7 is a perspective view of one of the terminal plates.

Similar characters of reference designate similar parts in each of the several views.

In the form of embodiment of the invention illustrated in Figures 1, 2 and 3, the brush 1 is cut away at both its forward and rear faces to provide shoulders 2, the lower edge of each of which is provided with arcuate recesses 3, the purpose of which is explained hereinafter. A pair of holes 4 extend transversely through the brush, these holes being provided for receiving internally threaded sleeves 5,r the purpose of which will hereinafter appear. Two pairs of pigtails' designated 6 and 6a are secured to the brush, each pair of pigtails consisting of a Singlecable, the strands of which are spread Serial No. 549,229.

out at the middle as indicated in Figure 6. The spreading operation is preferably performed by a pair of dies, one member of which 1s equipped with prongs for entering between the strands and spreading them apart at two points 7 and 8, as indicated in Figure 6. In this manner the pigtail is flattened and the holes 7 and 8 are formed without breakage of the individual strands, so that after the connection has been vassembled, no loose ends will appear.

To secure the pig-tails against the brush, I provide terminal plates 9 formed of sheet metal, preferably copper, and punched out to have the shape indicated in Figure 7. Screws 10 extend through plates 9 and cooperate with the opposite ends of sleeves 5 to securely clamp the pigtails against the brush material. The heads of screws 10, it will be observed, are flush with the terminal plates 9, these plates being-provided with countersunk parts 11 for accommodating the heads yof the screws. These countersunk portions of the terminal plates 9, moreover, extend into 'the pigtails and thus serve to prevent lateral sliding movement thereof.

It will be observed that in the present form of construction the pigtails are not only spread out to present a large contact area, butk are pressed into direct contact with the faces of the brush, so that the contact resistance is reduced to a minimum, this being particularly true because the cable, owing to its flexibility, will adapt itself perfectly to the face of the brush when the screws 10 are tightened. There will be no tendency to warp and consequently no impairment of the contact.

The terminal plates 9 are provided with flanges 12 adjacent their ends, the purpose of which is to prevent any loose strands from coming out at the ends. A flange 13 is provided for a similar purpose at the top of each plate.

The preferable manner of assembling the brush connection is as follows. After the brush has been machined to size and the shoulders 2 and holes 4 have been formed therein. theL material of the brush is coated with copper in any suitable manner, as by electroplating, and thereupon tinned, all excess solder being removed. Only the upper end of the brush is so treated, the coatying extending downward an approximate distance indicated by line la (Figure 1). .The cable is then flattened and formed in the die in the manner hereinbefore described, and the flattened portion of the cable is also given a coating of tin. A similar coating is given to the terminal plates 9, the sleeves 5 and the screws 10. The various parts of the connection are then assembled loosely on the brush and thereupon heated on a plate to the melting point of the solder or tin. The screws 10 are then securely tightened and any excess of tin or solder is wiped ofi' after this operation, so that there will be no tendency for the same to run out When the brush is placed into operation and accidentally becomes heated to an abnormal degree;

order to eliminate as far possible all pockets in which the melted solder may collect during the 'assembling operation, the lower edges of the terminal plates and the shoulders 2 are shaped to correspond to the outline of the flattened portion of the pigtails. 1n the illustrated form of embodiment the said plates are provided Vwith arcuate projections 3, substantially .concentric with screws 10, and the shoulders 2 are provided with similarly shaped recesses into which the said projections extend. Pockets or recesses are thus practically eliminated, and the accumulation of solder during the assembling operation is prevented. The danger of the formation of drops of solder, even during periods of serious overheating` of the brush when in actual use, is thus minimized.

1t will thus be observed that the present form of construction provides an extraordinarily large area of direct contact between the pig-'tail and the brush material and therefore an extremely low contact resistance. 1t has, moreover, the advantage of holding lit'- tle, if any, excess solder or tin, so that the brushes may safely be subjected to high temperatures.

The form of embodiment illustrated in Figures 4L and 5 differs from tie form previously described in that it has but a single pair `of pig-tails. 1n this form of construction the brush is provided with only one recessed shoulder 2 and the holes 4 are of smaller diameter, suflicient to accommodate the Shanks of screws 10. rlhe rear end of each hole is enlarged to accommodate a sleeve 15 which cooperates With the threaded portion of screws 10 to clamp Vthe flattened portion of the pig-tail cable against the face of the brush. To facilitate the fastening of the screws, the rear ends of sleeves 15 are provided with screw-driver slots 16, as indicated in Figure 5. In other respects the parts of the connection are substantially the same as vthose of the form of embodiment hereinbefore described. l A

Although 1 have herein shown and described only certain specific forms of embodiment of the invention, it willA be readily understood that many changes and modifications may be made therein Within the spirit and scope of the invention, it being my intention to claim the same broadly in Whatever form its principles may be employed.

Vlhat 1 claim is:

l. 1n combination, a brush, a plurality of conductors there-for, a .conducting plate engaging each conductor, said plates and brush having corresponding` transverse openings, a sleeve in the opening of the brush, and a plurality of screws one extending into said sleeve from each side of the brush for clamping said plates into engagement with the side of the brush.

2. In combination, a brush, a plurality of conductors therefor, a terminal plate for each conductor, said brush having a plurality of transverse openings and said plates being provided With openings for registering with the openings in the brush, a threaded sleeve in each opening of the brush, and a pair of screws for each of said sleeves for cooperating therewith to bind said conductors and terminal plates against the opposite faces of the brush.

3. `lin con'ibination, a brush, a flexible conductor therefor, said conductor being spread apart at a portion of its length to provide a flat, elongate surface for engaging the brush, an elongate plate member for engaging the spread portion of the conductor for holding 'the same throughout said spread portion in direc-t engagement with the brush surface, and securing means for said plate member, said means being arranged so as to create pressure on the plate member in a direction normal to the surface thereof.

ln combination, a brushJ a flexible con ductor therefor, said conductor 'forming a pair of 'pigtail's for the brush and beingv flattened at its middle, and the strands thereof being spread apart at a plurality of points of said flattened portion, and means for securing said portion of the conductor directly against the side of the brush, said means comprising' a plurality of members extending through said openings in the pigtail.

5. In combination, a brush, a pigtail conductor therefor, said conductor having av flattened portion in engagement with a side of the brush, a terminal pla-'te for covering said flattened portion, and a plurality of fastening members extending through said plate and said 'pigtail to bind vthe same against the brush, said plate being provided with a plurality of counter-sunk portions for accommodating the heads of said fastening members, and entering said spread portions of the pigtails to prevent lateral sliding movement thereof.

6. In combination, a brush having in its face a recess extending to the outer edge of the face7 a pigtail for said brush, said pigtail being lattened to engage said brush at said recessed area, and means for holding said pigtail in engagement with said brush, said means comprising a terminal plate for covering the -igtail, said plate bein provided with a gauge for enga ing sai outer edge so as to retain the stran s of the pigtail in place.

7. In combination, a brush having a recess, a pair of pigtails therefor, said pigtails being comprised of a flexible stranded conductor flattened adjacent the middle and spread apart at a plurality of points to provide openings therein, a terminal plate for engaging the flattened portion of the conductor to secure the same against the Wall of the brush, said terminal plate and the Wall of said recess in the brush bein provided each ,with an arcuate edge to fol ow substantially the outline of the spread portion of the pigtail, and fastening members extending through said plates and through said openings in the pigtails.

n testimony whereof I have afiixed my signature to this specification.

WILLIAM SIEBENMORGEN. 

